EKG Interpretation

EKG Interpretation Sequence

Regular or Irregular

Rate

P wave

PR interval (normal 0.12-0.20)

QRS (less than 0.12)

ST segment

T wave

Ectopic beats

Regularity of the QRS complexes

Heart rate (HR)1500/small boxes= most precise HR calculation for regular rhythms

Countdown method: 300 – 150 – 100 – 75 – 60 - 50

6 second method (irregular rhythms):

Images: http://www.emergencyekg.com/graphics/Interactive_06.gifhttp://research.vet.upenn.edu/smallanimalcardiology/ECGTutorial/DeterminingHeartRate/tabid/4959/Default.aspx

P wave:

PR interval:

.12-.20sec

>5 boxes for PR is heart block

QRS complex:

<.12sec

ST segment:

T wave:

Ectopic Beats:

Waveforms, Intervals, Segments, and Complexes (Lead II)

Sinus Tachycardia Regular rhythmRate >100

Sinus Bradycardia Regular rhythmRate <60

Premature atrial contraction (PAC)Usually has regular underlying rhythmEarly atrial contraction causes early P

waveP wave usually abnormal in size, shape or

direction and can be hidden in preceding T wave

May initially have rate suppression after this beat

Premature atrial contraction (PAC)

Atrial Flutter Regular or irregularRate: atrial 250-400, ventricular variesP waves: Sawtooth deflections

Atrial Fibrillation Irregularly irregular, difficult to assess with

tachycardiaRate: Varies, Rapid Ventricular Rate (RVR)

is > 100 bpm, Rate Control is < 100 bpmP waves: fibrillatory

Premature Ventricular Contraction (PVC) Underlying rhythm regularNo P wave associated with the PVCEarly wide QRS (>0.12)May be in sequence (ex: couplet, triplet,

bigeminy, trigeminy)

Ventricular Tachycardia (VT) Regular rhythmRate 140-250No P wave associated with VT QRS wide (>0.12)

Ventricular FibrillationNo rhythm – P wave and QRS wave

absentNo rateWavy irregular deflections of various sizes

and shapes seen

Pacemakers Paced beat will have “pacer spike” on EKGCan be 100% paced If underlying rate is greater then pacer

maker settings the pace maker will be inhibited and you will only see the underlying rhythm on EKG

Can be mixed paced beats and native rhythm

A-V paced (both atria and ventricle are paced, will have two pacer spikes per QRS)

Pacemakers

CASE STUDIES